Standards of Standards of MeasurementMeasurement

Section 1-2Section 1-2

Units and StandardsUnits and Standards

• Units must be included in order for a Units must be included in order for a measurement to make sense.measurement to make sense.

Ball of string just says 150 (no unit) is it 150 Ball of string just says 150 (no unit) is it 150 feet, inches, meters?feet, inches, meters?

Metric units include meters, centimeters, Metric units include meters, centimeters, kilograms, grams, etckilograms, grams, etc

• Standard is an exact quantity used for Standard is an exact quantity used for comparisoncomparison

ExampleExample

No meter stickNo meter stick Will the desk fit through the door?Will the desk fit through the door? Measure with my handsMeasure with my hands Measure with your handsMeasure with your hands No standard!No standard!

International System of UnitsInternational System of Units

Abbreviated Abbreviated SISI from the French from the French Le Le Systeme Internationale d’UnitesSysteme Internationale d’Unites

Improved version of the metric Improved version of the metric systemsystem

Each SI measurement has a Base Each SI measurement has a Base unitunit• Length – meterLength – meter• Mass - kilogramMass - kilogram

SI PrefixesSI Prefixes

Based on Multiples of 10Based on Multiples of 10 MilliMilli

CentiCenti

DeciDeciMeter gram literMeter gram literKiloKilo

Converting SI UnitsConverting SI Units

BridgesBridges Top of Bridge = Bottom of BridgeTop of Bridge = Bottom of Bridge 1 meter = 10 dm1 meter = 10 dm 1 meter = 100 cm1 meter = 100 cm 1 meter = 1000 mm1 meter = 1000 mm 1000 meters = 1 km1000 meters = 1 km

Convert the following:Convert the following:

1.255 liters to ml1.255 liters to ml

3075 cm to m3075 cm to m

More conversions:More conversions:

11cm to mm11cm to mm

675 m to km675 m to km

345 mm to km345 mm to km

Measuring DistanceMeasuring Distance

Base unit = meterBase unit = meter Size of the object determines the unitSize of the object determines the unit Activity pg.17Activity pg.17

13mm is easier to understand than 13mm is easier to understand than 0.013m0.013m

Measuring VolumeMeasuring Volume

Volume = the amount of space an Volume = the amount of space an object occupies.object occupies.

Volume = L x W x h (for solids)Volume = L x W x h (for solids) Liquid volumes are measured in liters Liquid volumes are measured in liters

and milliliters.and milliliters. 1 Liter = 1dm1 Liter = 1dm33

1 Liter =1000 ml1 Liter =1000 ml 1 cm1 cm33 = 1 ml = 1 ml

ConversionsConversions

1.5 liters to ml1.5 liters to ml

1.5 liters to cm1.5 liters to cm33

Measuring MatterMeasuring Matter

Mass = quantity of matter in an Mass = quantity of matter in an object.object.• Ping pong ball and golf ball have the Ping pong ball and golf ball have the

same volume, but much different same volume, but much different massesmasses

Density = mass per unit volumeDensity = mass per unit volume• Unit for density could be g/cmUnit for density could be g/cm33

If an object has a mass of 10g and a If an object has a mass of 10g and a volume of 2 cmvolume of 2 cm33 • Density = 10g/2cmDensity = 10g/2cm33 or 5g/cm or 5g/cm33

Measuring Time and Temp.Measuring Time and Temp.

Base unit for time is secondsBase unit for time is seconds Base unit for temp. is KelvinBase unit for temp. is Kelvin

• Most scientific work is done using celsiusMost scientific work is done using celsius• 0 Kelvin is the coldest possible temp. 0 Kelvin is the coldest possible temp.

also know as “absolute zero”also know as “absolute zero”• 0 kelvin= -2730 kelvin= -27300C (273 degrees below C (273 degrees below

the freezing pt. of water)the freezing pt. of water)